The contents and connection of the first four books of the
psalms

The fourth Book is not so markedly separated from the third, as
the preceding three from one another; and specially the third from
the first two, because the third, while prophetically announcing the
blessing, describes a state of things which leaves the expectation
of divine interference to bring in the blessing in full play. The
first had given the great principles of the position of the Jewish
remnant in connection with the history of Christ; in the second,
they are viewed as outside Jerusalem; the third turns to the
condition of Israel as a nation restored to their land, but not yet
in the full blessing of Jehovah; the fourth, as I have said,
completes this by the coming of Messiah. This connects the nation
and Christ, as well as the nation and Jehovah. Thus the book is
introduced with the nation's connection with Jehovah, looking to His
returning and finally blessing them, that His beauty may be upon
them. The second psalm of the book shows Christ's connection with
the nation as man in this world; the third psalm (Ps. 92) gives, in
prophetic celebration, the great result, into the whole
establishment of which the Psalm 93 to Psalm 100 enter; then some
deeply interesting details as to Christ (Psalm 101, Psalm 102);
while the general result, as displaying Jehovah's ways, is treated
in the praises of Psalm 103, Psalm 104, as to Israel and the earth;
Jehovah's dealings from the beginning, and Israel's ways, on the
contrary, with Him, in Psalm 105, Psalm 106, which close the book.